Effects of companion crops on population dynamics of maize lethal necrosis disease vectors in Bomet County, Kenya

View/Open

Date

Author

Metadata

Abstract

Maize is the most consumed staple food crop in Kenya with a
per capita of 110kg. It is equally an important commercial crop
particularly in high potential areas. Currently, the presence of
Maize lethal necrosis disease (MLND) has constrained its
production. The disease is challenging to manage because it is a
co-infection of maize by two viruses, the Maize chlorotic
mottle virus and Sugarcane mosaic virus, which are vectored
mainly by C0111 thrips iFrankliniella Williamsi) and C0111 leaf
aphids (Rhopalosiphum maidis), respectively. This study was
carried out to assess the potential for companion crops to act as
traps or repellents for these vectors, thus contributing to vector
management. Trials were carried out in fanners' fields in
Bomet County. Treatments included Napier, coriander, millet,
sorghum and maize, arranged in a randomized complete block
design with four replicates for two seasons, November 2014-
April 2015 and April-August 2015. Each crop was planted
either as an intercrop or a border crop with maize as the main
crop. We present results from the first season. There were
significant differences (P<O.OO 1) in the presence of C0111 Thrips
among the companion crops although intercrops (21. 53)
recorded a slightly higher significant figure than border crops
(10.28). Coriander trapped the highest number of C0111 thrips
(27.6), followed by sorghum (22.2). Napier and millet trapped
the lowest mean number of thrips, 9.1 and 4.7, respectively.
However, in comparison with maize (85.96), companion crops
had significantly lower C0111 thrips, Coriander hosted the
highest number of aphids (132.6) compared with Napier (45.9)
and sorghum (30.8) while millet recorded the lowest (5.6). The
number of aphids in coriander and maize (60.4) was not
significantly different from each other but was significantly
higher compared with those registered in other companion
crops (P=O.0021). This preliminary study shows that both
Napier and millet may act as repellent crops for Com Thrips
mainly as border crops while coriander and sorghum could act
as trap crops majorly as intercrops.